Nano LIFE

Tissue engineering strategies for regenerating damaged cartilage using hydrogels have garnered significant attention due to the limited self-healing capacity of damaged cartilage tissue and the restrictions of current medical treatment methods. In particular, using human mesenchymal stem cells (hMSCs) as the cell source has shown the potential to differentiate along a chondrogenic lineage. Hydrogels, whether made of synthetic polymers, natural polymers, or combinations, are widely explored as scaffolding materials mimicking the natural cartilage environment. Based on the understanding of the importance of surface nanotopographies and mechanical stiffness, hydrogels have been presented in various forms and tested for the differentiation of hMSCs. The primary focus of this review is to provide a summary of recent advances in physically and chemically modified hydrogels promoting the chondrogenesis of hMSCs. Advances in micromachining have helped in forming surfaces with the required roughness or an array of micropillars of defined architecture. Hydrogels have been combined with various stimulants such as small peptides, growth factors, and many modified matrix elements. Creating anisotropic hydrogels mimicking the extracellular matrix of cartilage has also been reported. These studies show promising results and identify a niche for in-vitro differentiation of chondrocytes from hMSCs.

Nonviral gene delivery (NVGD) is an appealing alternative to viral gene delivery for clinical applications due to its lower cost and increased safety. A variety of promising nonviral vectors are under development, including cationic polymers, lipids, lipid-polymer hybrids (LPHs) and inorganic nanoparticles. However, some NVGD strategies have disadvantages that have limited their adoption, including high toxicity and low efficiency. This review focuses on the most common NVGD vehicles with an emphasis on recent developments in the field.

Photodynamic therapy (PDT) is a two-step procedure that involves the administration of special drugs, commonly called photosensitizers, followed by the application of certain wavelengths of light. The light activates these photosensitizers to produce reactive molecular species that induce cell death in tissues. There are numerous factors to consider when selecting the appropriate photosensitizer administration route, such as which part of the body is being targeted, the pharmacokinetics of photosensitizers, and the formulation of photosensitizers. While intravenous, topical, and oral administration of photosensitizers are widely used in preclinical and clinical applications of PDT, other administration routes, such as intraperitoneal, intra-arterial, and intratumoral injections, are gaining traction for their potential in treating advanced diseases and reducing off-target toxicities. With recent advances in targeted nanotechnology, biomaterials, and light delivery systems, the exciting possibilities of targeted photosensitizer delivery can be fully realized for preclinical and clinical applications. Further, in light of the growing burden of cancer mortality in low- and middle-income countries and development of low-cost light sources and photosensitizers, PDT could be used to treat cancer patients in low-income settings. This short article introduces aspects of interfaces of intratumoral photosensitizer injections and nano-biomaterials for PDT applications in both high-income and low-income settings but does not present a comprehensive review due to space limitations.

Cancer is one of the most prevalent diseases with mortality rate considerably increasing every year. Conventional treatment strategies for cancer like chemotherapy suffer from the drawbacks of multiple-dose requirements and non-specificity of drug action. Moreover, the cost involved in the diagnosis and treatment is very high. Recently, the application of nanotechnology in the field of cancer has witnessed tremendous significance due to the unique size, shape, and surface properties of nanomaterials. With the intention to utilize biocompatible and biodegradable nanomaterials in cancer and reduce the non-specificity, approaches such as targeted nanotherapeutics came into existence. Besides having therapeutic potential, some materials demonstrate their applicability in bioimaging forecasting distinct optical properties. In this review, we have discussed the basics and principles guiding the design of different photo-triggered nanotheranostic materials used in cancer. Additionally, recent developments and advantages offered by the NIR-responsive photodynamic and photothermal agents along with their future scope have been presented. An overview of the toxicity and clinical prospect of photosensitive agents is also summarized. Overall, the field of photo-triggered cancer nanotheranostics has huge potential that can be clinically translated into an affordable and safe treatment approach.

Biofabrication for tissue engineering and regenerative medicine is a rapidly evolving field that incorporates bioprinting or bioassembly for the development of biologically functional products with structural organization using cells, bioactive molecules, and biomaterials. Bioprinting is a biofabrication technology that utilizes biomaterials, living cells, and supporting materials, called bioink, to generate three-dimensional tissue constructs. Bioprinting offers several advantages over traditional scaffolding and microengineering methods such as precise architecture control, high reproducibility, and versatility. The ideal bioink should possess appropriate structural, mechanical, gelation, rheological, chemical, biological, degradation, and biomimetic properties for the desired application of the final product. Several natural and synthetic bioinks have been developed and this review has focused on conductive nanomaterials that have been used in combination with hydrogel materials for bioink synthesis.

Delivery of therapeutic compounds to the diseased area in the body with minimized adverse effects is the underlying objective behind development of advanced drug delivery systems. Providing disease-specific release patterns is the ultimate goal of any drug delivery system. Electrospinning has been widely used for nanofiber fabrication. Having high aspect ratio and similarity to the extracellular matrix in the body make electrospun nanofibers a great candidate to be used as drug delivery implants. In this study, we report electrospinning to be a tunable technique capable of providing engineered, disease-specific drug release patterns. Using “one factor at a time” and “central composite design” techniques, we respectively demonstrate flow rate and applied voltage to be the two most significant parameters (with $F$-values of 512.48 and 42.31) affecting the final fiber diameter, and capillary-to-collector distance as the least important one, by evaluating their influence, individually and combined, on the morphology of electrospun Poly (Lactide-co-Glycolide acid) nanofibers. Using the same two techniques, we also show that hydrophobicity of the polymeric fibrous scaffold, measured by water contact angle (WCA) with the $F$-value of 376.44, is the main factor to consider when designing an electrospun fibrous drug delivery system for a specific disease, while fiber diameter can further modulate the release pattern of the drug from hydrophobic polymeric nanofibers. We finally support our hypothesis by comparing our findings with analysis of data derived from the literature. Taken together, our findings suggest electrospinning to be a tunable technique capable of providing various release patterns for any small molecular weight drug on the basis of the requirements of the diseases to be treated.