Peripheral nerve regeneration strategies employ the use of polymeric engineered nerve conduits encompassed with components of a delivery system. This allows for the controlled and sustained release of neurotrophic growth factors for the enhancement of the innate regenerative capacity of the injured nerves. This review article focuses on the delivery of neurotrophic factors (NTFs) and the importance of the parameters that control release kinetics in the delivery of optimal quantities of NTFs for improved therapeutic effect and prevention of dose dumping. Studies utilizing various controlled-release strategies, in attempt to obtain ideal release kinetics, have been reviewed in this paper. Release strategies discussed include affinity-based models, crosslinking techniques, and layer-by-layer technologies. Currently available synthetic hollow nerve conduits, an alternative to the nerve autografts, have proven to be successful in the bridging and regeneration of primarily the short transected nerve gaps in several patient cases. However, current research emphasizes on the development of more advanced nerve conduits able to simulate the effectiveness of the autograft which includes, in particular, the ability to deliver growth factors.

The risk of secondary bacterial infections resulting from dental procedures has driven the design of antimicrobial and antifouling dental materials to curb pathogenic microbial growth, biofilm formation and subsequent oral and dental diseases. Studies have investigated approaches based primarily on contact-killing or release-killing materials. These materials are designed for addition into dental resins, adhesives and fillings or as immobilized coatings on tooth surfaces, titanium implants and dental prosthetics. This review discusses the recent developments in the different classes of biomaterials for antimicrobial and antifouling dental applications: polymeric drug-releasing materials, polymeric and metallic nanoparticles, polymeric biocides and antimicrobial peptides. With modifications to improve cytotoxicity and mechanical properties, contact-killing and anti-adhesion materials show potential for incorporation into dental materials for long-term clinical use as opposed to short-lived antimicrobial release-based coatings. However, extended durations of biocompatibility testing, and adjustment of essential biomaterial features to enhance material longevity in the oral cavity require further investigations to confirm suitability and safety of these materials in the clinical setting. The continuous exposure of dental restorative and regenerative materials to pathogenic microbes necessitates the implementation of antimicrobial and antifouling materials to either replace antibiotics or improve its rational use, especially in the day and age of the ever-increasing problem of antimicrobial resistance.

The focus of significance in neuronal repair strategies is the design of scaffold systems capable of promoting neuronal regeneration and directional guidance via provision of a biomimetic environment resemblance of native neural tissue. The purpose of this study was to synthesize triple-cue electrospun aligned nanofibrous films (physical cue) of poly(3-hyroxybutyric acid-co-3-hydroxyvaleric acid) (PHBV) blended with magnesium-oleate (MgOl) (chemical cue) and N-acetyl-L-cysteine (NAC) (therapeutic cue) with potential incorporation into hollow nerve guidance conduits for an enhanced regenerative strategy. A Box–Behnken experimental design of 15 formulations, were analysed for crystallinity, textural properties and in vitro water-uptake, erosion, NAC-release and PC12 cell viability. Nucleating effects of MgOl provided tuning of PHBV electrospinning-induced crystallinity and mechanical properties. Tensile strengths and deformation moduli of ±12 MPa and ±7 MP, respectively, were attainable, thereby matching native nerve mechanics. Crystallinity changes ascribed differing release kinetics to NAC over 30 d: diffusion-based (42%–58% crystallinity with 33%–47% fractional release) and polymer-relaxational (59%–65% crystallinity with 60%–82% fractional release). The synergistic activity of MgOl and NAC increased PC12 proliferation by 32.6% compared to the control. MgOl produced dual actions as non-toxic plasticiser and PC12 cell proliferation-promoter via nucleation and neurotrophic-like effects, respectively. Controlled release of NAC imparted neuro-protectant effects on PC12 cells and promoted neurite extension, thus, making electrospun PHBV-MgOl nanofibrous films a versatile and promising approach for axonal guidance in peripheral nerve repair strategies.

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Biocompatible, attuned, and congruent stimuli-responsive polymers of synthetic and plants and animals-based origins are essential raw materials for constructing bio-matching scaffolds, devices, and vehicles for payload deliveries, tissue engineering, therapeutics, and diagnostic purposes, and also as fill-in materials at biosites for various biomimetic applications. The nanobiomaterials for nanobiotechnology, nanopharmaceuticals, and nanobioengineering requires to have fit-in intrinsic chemical, physical, physico-chemical, mechanical, biological, and chemo-biological characteristics. The developed nanomaterials are also required to be receptive and biomimicking in quality, and they must not be toxic at any stage of use or implantation, minimally or of zero order degradation together with aging and use-related degradation, and last a life-time. The biomaterial at the upgraded scale needs to possess intricate characteristics equivalent to the biological materials, and compatible to the biological-sites during transportation, delivery, and site-unloading, and use. Recent developments in nanobiomaterial substrate designs and structure, characteristics, design requirements, chemo-biological interface related bio-systems response-compatibility, biomaterial synchronized, contemporaneous, and evolving applications in health care, therapeutics, nanomedicine, bio-hazard prevention, toxicity and ways of toxicity-control are outlined. The structure-function relationship, scope and limitations, structural and functional classes, and diversified biological outreach are discussed.

The gellan-xanthan ratio variability and the pore-inducing effects of intercalated PMMA yielded a means for fine tuning the mechanical attributes of the hydrogel matrices, particularly matrix rigidity and flexibility, offering an appealing strategy for the design and development of synthetic bioactive-releasing peripheral nerve repair conduits.

Ionic liquids are a potent class of organic compounds exhibiting unique physico-chemical properties and structural compositions that are different from the classical dipolar organic liquids. These molecules have found diverse applications in different chemical, biochemical, biophysical fields, and a number of industrial usages. The ionic liquids-based products and procedural applications are being developed for a number of newer industrial purposes, and academic uses in nanotechnology related procedures, processes, and products, especially in nanobiotechnology and nanomedicine. The current article overviews their uses in different fields, including applications, functions, and as parts of products and processes at primary and advanced levels. The application and product examples, and prospects in various fields of nanotechnology, domains of nanosystem syntheses, nano-scale product development, the process of membrane filtering, biofilm formation, and bio-separations are prominently discussed. The applications in carbon nanotubes; quantum dots; and drug, gene, and other payload delivery vehicle developments in the nanobiotechnology field are also covered. The broader scopes of applications of ionic liquids, future developmental possibilities in chemistry and different bio-aspects, promises in the newer genres of nanobiotechnology products, certain bioprocesses controls, and toxicity, together with emerging trends, challenges, and prospects are also elaborated.

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