Hybrid laser technology for Biomaterials : 

Biomaterials are used for the reparation or reconstruction of the musculo-skeletal system and soft tissue regeneration as well as in various medical instruments and devices. The potential range of applications for biomaterials is rapidly increasing, with different physical, mechanical and medical properties required for different applications. One flexible and widely used method for the fast preparation and testing of biomaterials is pulsed laser deposition (PLD). The use of PLD for biomaterials and improvements to the technique that will allow the fabrication of materials with very specific biocompatible properties. Some practical applications of PLD and hybrid PLD in the field of biomaterials.

Biomaterials for Cell Targeting :

Cell targeting is an interesting prospect for drug delivery because it offers a potential avenue for drug optimization, as well as opening the possibility of the development of new drug therapies. Biomaterials can be a potential prospect because the properties of the compounds inherent to the biomaterials can be harnessed to be directed by the body to the cell of interest. Polymers, from buckminsterfullerenes to nanofibers, can be altered to contain side-chains that will interact with certain cell surface receptors, and metals can be used in conjunction with organic compounds to give interesting properties to otherwise inert compounds, as in the case of metallofullerenes.

Cell targeting is an interesting prospect for drug delivery because it offers a potential avenue for drug optimization, as well as opening the possibility of the development of new drug therapies. Biomaterials can be a potential prospect because the properties of the compounds inherent to the biomaterials can be harnessed to be directed by the body to the cell of interest. Polymers, from buckminsterfullerenes to nanofibers, can be altered to contain side-chains that will interact with certain cell surface receptors, and metals can be used in conjunction with organic compounds to give interesting properties to otherwise inert compounds, as in the case of metallofullerenes.

Nanofabricated Scaffolds : 

While critical insights into 2D cell-nanotopography interactions are now enabling us to direct cell behavior, considerable efforts have been made to develop 3D artificial scaffolds at the nanoscale for tissue engineering applications. Nanofibrous scaffolds are now under wide investigation as they exhibit a very similar physical structure to protein nanofibers in ECM. Among the three dominant nanofabrication methods, electrospinning is a very simple and practical technique, suitable for the creation of aligned and complex 3D structures; self-assembly technology emulates the process of ECM assembly and can thus produce very thin nanofibers; and phase separation allows for continuous fiber network fabrication with tunable pore structure, and the formation of sponge-like scaffolding. Nanocomposites based scaffolds (e.g. nano-hydroxyapatite/collagen) are, on the other hand, very popular in hard-tissue engineering, particularly for the reconstruction of bone tissue. Beyond nanofibers and nanocomposites, carbon nanotubes have also attracted attention due to their mechanical strength and electrical conductivity, and because they can be readily incorporated into 3D architectures.

MEM/NEM devices for drug delivery : 

The field of micro-/nanoelectromechanical (MEM/NEM) device-based drug delivery has also made significant headway over the past decade. In particular, implantable microchips containing nanosized reservoirs have been developed to deliver drugs for long time periods in a precisely controlled manner; microneedles are being tested in painless transdermal drug delivery; and the incorporation of nanofeatures (e.g. nanopores, nanochannels, and nanoparticles) in microfabricated systems are perfecting drug delivery and immunoisolation techniques. Intriguingly, these devices can be further modified to deliver new therapeutics, achieve targeted delivery, and co-deliver multiple agents. Substantial efforts are also being put into creating intelligent devices that could potentially sense when and how much dose is needed and then automatically release it from reservoirs. To do this, one feat that must be met is the continuous and stable monitoring of physical and biochemical conditions, in situ. The recent development of nanotechnology-based sensors (e.g. nanowire and nanotube) may offer new ways to address this concern, and could even facilitate device miniaturization.

Cell-Nanotopography Interactions : 

Living cells are highly sensitive to local nanoscale topographic patterns within ECM. In the pursuit to control cell function by underlying nanotopographic cues, engineered substrates with different nanofeatures have become rapidly adopted. Top-down lithographic techniques are now utilized to create various nanopatterns, such as gratings, pillars, and pits, in a precisely controlled manner. Techniques like micelle lithography, anodization, and electrospinning can also be used to create an array of nanospheres, vertical nanotubes, and nanofibers. Additionally, less-ordered nanotopographies are now being fabricated by polymer demixing, chemical etching, electrospinning, and phase separation processes.

Nanotechnology in Drug Delivery and Tissue Engineering

Nanotechnology in Drug Delivery and Tissue Engineering : 

The application of nanotechnology in medicine, referred to as nanomedicine, is offering numerous exciting possibilities in healthcare.

Drug delivery

Nanoscale delivery vehicles can (1) enhance the therapeutic efficacy and minimize adversities associated with available drugs; (2) enable new classes of therapeutics; and (3) encourage the re-investigation of pharmaceutically suboptimal but biologically active new molecular entities that were previously considered undevelopable.

Tissue engineering

Nanotechnology can enable the design and fabrication of biocompatible scaffolds at the nanoscale and control the spatiotemporal release of biological factors—resembling native extracellular matrix—to direct cell behaviors, and eventually lead to the creation of implantable tissues.

Applications of Nanoengineered scaffolds in Tissue growth and Regenerative medicine:

It is becoming increasingly evident that interaction between cells and their microenvironment at the nanoscale level can reorganize cytoskeleton and induce specific cell signaling that regulates the fate of the cell. Thus, nanostructured scaffolds that mimic the tissue-specific microenvironment have been of great interest in nanotechnology for tissue engineering and regenerative medicine. Scaffolds with biochemical, mechanical, and electrical properties similar to those of native tissues have been nanoengineered to enhance cell adhesion, proliferation, differentiation, and even maturation, thereby fostering cell function and tissue growth.

An extracellular matrix-like architecture can be fabricated by nanopatterning, electrospinning, self-assembly, conjugation of adhesion motifs to the matrix backbone, or sulfating the matrix backbone. The properties of this extracellular matrix-like architecture can be adjusted by incorporation of nanomaterials such as carbon nanotubes, nanowires, and nanoparticles. For instance, developed an electrically conductive hybrid hydrogel scaffold based on gold nanoparticles homogeneously synthesized throughout a polymer template gel. The expression of connexin-43 increased in neonatal cardiomyocytes grown on the scaffold, suggesting that an electrically active scaffold impregnated with gold can enhance cardiomyocyte function.

Stem cell application for Osteoarthritis in the Knee joint : 

Self-regeneration of the cartilage, which includes chondrocytes, ground substance (cartilage matrix) and elastin fibers, is a slow process which results in new cartilage substance that is not stable for intensive burdens. The fluid inside the joint contains mesenchymal stem cells (MSCs) which can differentiate into chondrocytes, but new deposited cartilage is very fragile and can be destroyed by applying a minimal amount of stress on the joint. Additionally there is only a limited quantity of MSCs in the joint available to differentiate and the process of differentiation is slow.

Nanotechnology for Tissue Engineering : 

Tissue engineering is very fast growing scientific area in this era which is used to create, repair, and/or replace cells, tissues and organs by using cell and/or combinations of cells with biomaterials and/or biologically active molecules and it helps to produce materials which very much resembles to body’s native tissue/tissues. From tissue engineering current therapies got revolutionised and life quality of several millions patient got improved. Tissue engineering is the connecting discipline between engineering materials science, medicine and biology. In typical tissue engineering cells are seeded on biomimicked scaffold providing adhesive surfaces, then cells deposit their own protein to make them more biocompatible, but unable to vascularise properly, lack of functional cells, low mechanical strength of engineered cells, not immunologically compatible with host and Nutrient limitation are a classical issue in the field of tissue and tissue engineering.

Tissue engineering in Endodontics :

The vitality of dentin-pulp complex is fundamental to the life of tooth and is a priority for targeting clinical management strategies. Loss of the tooth, jawbone or both, due to periodontal disease, dental caries, trauma or some genetic disorders, affects not only basic mouth functions but aesthetic appearance and quality of life. One novel approach to restore tooth structure is based on biology: regenerative endodontic procedure by application of tissue engineering. Regenerative endodontics is an exciting new concept that seeks to apply the advances in tissue engineering to the regeneration of the pulp-dentin complex. The basic logic behind this approach is that patient-specific tissue-derived cell populations can be used to functionally replace integral tooth tissues. The development of such ‘test tube teeth’ requires precise regulation of the regenerative events in order to achieve proper tooth size and shape, as well as the development of new technologies to facilitate these processes.

Biomaterials for Artificial Organs:

The worldwide demand for organ transplants far exceeds available donor organs. Consequently some patients die whilst waiting for a transplant. Synthetic alternatives are therefore imperative to improve the quality of, and in some cases, save people’s lives. Advances in biomaterials have generated a range of materials and devices for use either outside the body or through implantation to replace or assist functions which may have been lost through disease or injury. Biomaterials for artificial organs reviews the latest developments in biomaterials and investigates how they can be used to improve the quality and efficiency of artificial organs. Biomaterials including membranes for oxygenators and plasmafilters, titanium and cobalt chromium alloys for hips and knees, polymeric joint-bearing surfaces for total joint replacements, biomaterials for pacemakers, defibrillators and neurostimulators and mechanical and bioprosthetic heart valves. Part two goes on to investigate advanced and next generation biomaterials including small intestinal submucosa and other decullarized matrix biomaterials for tissue repair, new ceramics and composites for joint replacement surgery, biomaterials for improving the blood and tissue compatibility of total artificial hearts (TAH) and ventricular assist devices (VAD), nanostructured biomaterials for artificial tissues and organs and matrices for tissue engineering and regenerative medicine.

Biomaterials for artificial organs is an invaluable resource to researchers, scientists and academics concerned with the advancement of artificial organs.

Recent advances in stem cells and regenerative medicine

Recent advances in Stem Cells and Regenerative Medicine:

There have been many recent advances in our understanding of stem cell biology, tissue regeneration and organ repair mechanisms. This is accompanied by a significant increase in the number of stem cell therapy, cell therapy and regenerative medicine studies being published. These studies range from basic studies in animal models to clinical trials. This increased potential for regenerative medicine is timely, given the increasing burden of chronic disease and disability. Although pharmaceutical approaches to chronic disease have been transformative, many diseases result in chronic organ and tissue damage that is unlikely to be solved through conventional pharmaceutical approaches. To tackle these chronic and important disabling conditions, it is likely that a new approach will be required which has been termed regenerative medicine. The broad approaches of regenerative medicine are: (i) to understand the intrinsic repair mechanisms within tissues to try and promote these to improve healthy regeneration and reduce pathological wound healing responses such as excessive scarring and (ii) develop cell therapies whereby exogenous cells can be transplanted into tissues to help repair the damaged tissue or organs. With an improved understanding of stem cell biology and tissue repair mechanisms there have also been rapid advances in the creation of artificial substrates or artificial niches for stem cells to grow upon. Stem cell niches within tissue are special environments defined by both the cellular and the extracellular environment in which stem cells reside. Stem cell niches help to tightly regulate the growth and differentiation of the stem cells into their daughter cells within tissue. In conditions of severe tissue damage, such as liver cirrhosis, the niche can become so abnormal that even transplanted cells cannot readily en-graft and grow normally. In this situation strategies to improve the niche, for example, by reducing scarring are required to improve regeneration or allow successful cell therapy. It is also likely that artificial stem cell niches will be developed where stem cells can grow upon prior to transplantation of this composite graft.

Tissue Engineering and Stem Cell Research : 
There is significant potential in the orofacial complex for fracture healing, bone augmentation, TMJ cartilage repair or regeneration, pulpal repair, periodontal ligament regeneration, and osseointegration for implants. Regenerative treatments require the three key elements: an extracellular matrix scaffold (which can be synthetic), progenitor/stem cells, and inductive morphogenetic signals. The oral cavity offers special advantages over other parts of the body for tissue engineering because there is ready access and ease of observation. At the present time, the signaling processes that control the development of discrete dental morphologies for incisors, canines, premolars, and molars are not clear. Successful bioengineering of recognizable tooth structures has been reported using cells from dissociated porcine third molar tooth buds seeded on biodegradable polymer scaffolds that were grown in rat hosts for twenty to thirty weeks. Successful bioengineering has demonstrated that mature tooth structures form single-cell suspensions of four-day postnatal cultured rat tooth bud cells on polylactic acid scaffolds grown as implants in the omenta of adult rat hosts over twelve weeks. Murine teeth have been produced recently using stem cell-based engineering techniques.

Biomaterials for Drug Delivery Systems : 

Drug delivery systems have unusual materials requirements which derive mainly from their therapeutic role: to administer drugs over prolonged periods of time at rates that are independent of patient-to-patient variables. The chemical nature of the surfaces of such devices may stimulate biorejection processes which can be enhanced or suppressed by the simultaneous presence of the drug that is being administered. Selection of materials for such systems is further complicated by the need for compatibility with the drug contained within the system. A review of selected drug delivery systems is presented. This leads to a definition of the technologies required to develop successfully such systems as well as to categorize the classes of drug delivery systems available to the therapist.

There are five major challenges to the Biomaterials scientist:

1. How to minimize the influence on delivery rate of the transient biological response that accompanies implantation of any object
2. How to select a composition, size, shape, and flexibility that optimizes biocompatibility 
3. How to make an intravascular delivery system that will retain long-term functionality
4. How to make a percutaneous lead for those delivery systems that cannot be implanted but which must retain functionality for extended periods
5. How to make biosensors of adequate compatibility and stability to use with the ultimate drug delivery system-a system that operates with feedback control.

Emerging Trends in Biomaterials Research :

Across the broad spectrum of our field, biomaterials permeate nearly everything we do. Advances in biomaterials technology often have a ripple effect, and collectively, these advances elevate our entire field. Therefore, this special issue is focused on emerging trends in biomaterials ranging from the nanoscale to the macroscale, for a wide range of biomedical applications, including therapeutic delivery, immunotherapy, bioimaging, and regenerative engineering.

Traditionally, single component biomaterials have suffered from serious limitations due to limited control over biophysical and biochemical characteristics, hampering their utility for biomedical applications. To overcome these limitations, a range of advanced biomaterials are designed with multiple functionalities to guide cell behavior. This special issue emphasizes the design and development of the next generation of smart and responsive biomaterials to address these challenges. The original research articles capture the growing trend of functional biomaterials, and the review articles provide a critical evaluation of emerging trends in designing the next generation of biomaterials.

Engineering new biomaterials from natural sources such as marine sponges and decellularized tissues (cartilage) (Boccaccini, Detamore) are used to mimic biophysical and biochemical characteristics of native tissues. Other approaches include engineering natural polymers such as gelatin and alginate to co-encapsulate cells and therapeutics for guiding cellular functions (Mikos, Moshaverinia). Cell-instructive biomaterials are designed by incorporating biochemical clues to promote, augment, and facilitate regeneration of the damaged tissues (Burdick, Gu, Garcia, Bryant). These studies highlight that controlling cell-material interactions is necessary for modulating cellular functions.

“Smart” biomaterials are another emerging class of materials that respond to multiple external stimuli. For example, biomaterials responding to pH or cell-secreted enzymes can be used for on-demand and local delivery of therapeutics to regulate cell responses (Peppas, Segura). By utilizing the physicochemical characteristics of smart biomaterial, effective delivery of labile biomolecules is proposed for immunomodulation and long-term disease management (Mitragotri, Tasciotti). Smart and responsive biomaterials with multiple functionalities are promising biomaterials for a range of biomedical applications.

Nanoengineered biomaterials present significant opportunities to design materials with custom properties. By incorporating nanoparticles within a polymeric network, biomaterials with tailored functionality have been developed. A range of two- and three-dimensional nanomaterials have been shown to physically or chemically interact with the polymers, yielding new characteristics of the nanoengineered network (Sitharaman). Nanocomposite biomaterials with tailored functionality have opened up new possibilities for modulating cellular behavior for tissue engineering, localized drug delivery, and osteoarthritis (Sant, Zhang, Singh).

Advanced manufacturing technologies such as microfabrication and 3D printing enable mimicry of complex tissue architectures and can provide the essential cellular microenvironment to guide the formation of functional tissues. For example, microscale geometric patterning of ECM proteins can be leveraged to control cell alignment and differentiation (Feinberg). These microfabricated structures may be employed for in vitroapplications in toxicity screening, disease modeling and drug discovery. Another emerging approach to pattern and guide cell behavior is 3D printing. A vital aspect and bottleneck to the design and implementation of a bioprinting system is a lack of suitable bioinks that are printable and can guide cell functions (Gaharwar). To address these challenges, a range of advanced bioink formulations is designed including multicomponent systems, interpenetrating networks, nanoengineered bioinks and supramolecular networks.

Tissue Engineering applications in Therapeutic Cloning :

Few treatment options are available for patients suffering from diseased and injured organs because of a severe shortage of donor organs available for transplantation. Therapeutic cloning, where the nucleus from a donor cell is transferred into an enucleated oocyte in order to extract pluripotent embryonic stem cells, offers a potentially limitless source of cells for replacement therapy. Scientists in the field of tissue engineering apply the principles of cell transplantation, material science, and engineering to construct biological substitutes that will restore and maintain normal function in diseased and injured tissues.

Porous Scaffold design for Tissue Engineering : 

A paradigm shift is taking place in medicine from using synthetic implants and tissue grafts to a tissue engineering approach that uses degradable porous material scaffolds integrated with biological cells or molecules to regenerate tissues. This new paradigm requires scaffolds that balance temporary mechanical function with mass transport to aid biological delivery and tissue regeneration. Little is known quantitatively about this balance as early scaffolds were not fabricated with precise porous architecture. Recent advances in both computational topology design (CTD) and solid free-form fabrication (SFF) have made it possible to create scaffolds with controlled architecture.

Biomaterials in future Healthcare :

Biomaterials are being used for the healthcare applications from ancient times. But subsequent evolution has made them more versatile and has increased their utility. Biomaterials have revolutionized the areas like bioengineering and tissue engineering for the development of novel strategies to combat life threatening diseases. Together with biomaterials, stem cell technology is also being used to improve the existing healthcare facilities. These concepts and technologies are being used for the treatment of different diseases like cardiac failure, fractures, deep skin injuries, etc. Introduction of nanomaterials on the other hand is becoming a big hope for a better and an affordable healthcare. Technological advancements are underway for the development of continuous monitoring and regulating glucose levels by the implantation of sensor chips. Lab-on-a-chip technology is expected to modernize the diagnostics and make it more easy and regulated. Other area which can improve the tomorrow’s healthcare is drug delivery. Micro-needles have the potential to overcome the limitations of conventional needles and are being studied for the delivery of drugs at different location in human body. There is a huge advancement in the area of scaffold fabrication which has improved the potentiality of tissue engineering. Most emerging scaffolds for tissue engineering are hydrogels and cryogels. Dynamic hydrogels have huge application in tissue engineering and drug delivery. Furthermore, cryogels being supermacroporous allow the attachment and proliferation of most of the mammalian cell types and have shown application in tissue engineering and bioseparation. With further developments we expect these technologies to hit the market in near future which can immensely improve the healthcare facilities.