Chitta Ranjan Patra

In this report, we have designed a simple and efficient green chemistry approach for the synthesis of colloidal silver nanoparticles (b-AgNPs) that is formed by the reduction of silver nitrate (AgNO3) solution using Olax scandens leaf extract. The colloidal b-AgNPs, characterized by various physico-chemical techniques exhibit multifunctional biological activities (4-in-1 system). Firstly, bio-synthesized silver nanoparticles (b-AgNPs) shows enhanced antibacterial activity compared to chemically synthesize silver nanoparticles (c-AgNPs). Secondly, b-AgNPs show anti-cancer activities to different cancer cells (A549: human lung cancer cell lines, B16: mouse melanoma cell line & MCF7: human breast cancer cells) (anti-cancer). Thirdly, these nanoparticles are biocompatible to rat cardiomyoblast normal cell line (H9C2), human umbilical vein endothelial cells (HUVEC) and Chinese hamster ovary cells (CHO) which indicates the future application of b-AgNPs as drug delivery vehicle. Finally, the bio-synthesized AgNPs show bright red fluorescence inside the cells that could be utilized to detect the localization of drug molecules inside the cancer cells (a diagnostic approach). All results together demonstrate the multifunctional biological activities of bio-synthesized AgNPs (4-in-1 system) that could be applied as (i) anti-bacterial & (ii) anti-cancer agent, (iii) drug delivery vehicle, and (iv) imaging facilitator. To the best of our knowledge, there is not a single report of biosynthesized AgNPs that demonstrates the versatile applications (4-in-1 system) towards various biomedical applications. Additionally, a plausible mechanistic approach has been explored for the synthesis of b-AgNPs and its anti-bacterial as well as anti-cancer activity. We strongly believe that bio-synthesized AgNPs will open a new direction towards various biomedical applications in near future.

One of the key challenges in anticancer therapy is the toxicity and poor bioavailability of the anticancer drugs. Nanotechnology can play a pivotal role by delivering drugs in a targeted fashion to the malignant cells that will reduce the systemic toxicity of the anticancer drug. In this report, we show a stepwise development of a nanoparticle-based targeted delivery system for in vitro and in vivo therapeutic application in pancreatic cancer. In the first part of the study, we have shown the fabrication and characterization of the delivery system containing gold nanoparticle as a delivery vehicle, cetuximab as a targeting agent, and gemcitabine as an anticancer drug for in vitro application. Nanoconjugate was first characterized physico-chemically. In vitro targeting efficacy, tested against three pancreatic cancer cell lines (PANC-1, AsPC-1, and MIA Paca2) with variable epidermal growth factor receptor (EGFR) expression, showed that gold uptake correlated with EGFR expression. In the second part, we showed the in vivo therapeutic efficacy of the targeted delivery system. Administration of this targeted delivery system resulted in significant inhibition of pancreatic tumor cell proliferation in vitro and orthotopic pancreatic tumor growth in vivo. Tumor progression was monitored noninvasively by measuring bioluminescence of the implanted tumor cells. Pharmacokinetic experiments along with the quantitation of gold both in vitro and in vivo further confirmed that the inhibition of tumor growth was due to targeted delivery. This strategy could be used as a generalized approach for the treatment of a variety of cancers characterized by overexpression of EGFR.

Chronic wounds have emerged as a major cause of mortality, especially in patients with diabetes and other pathologies. Statistics indicate that chronic wounds affect around 6.5 million patients annually, with wound care and management incurring huge economic costs. Growing incidence of chronic wounds and associated pathologies along with the limitations of current therapies have established a strong need for novel and innovative approaches to accelerate wound healing. Conventionally, chronic wounds are addressed using various FDA-approved silver-based formulations and other biomaterials. However, the toxicity associated with these conventional approaches, along with the increased frequency of chronic wound cases, makes the development of alternative therapies for effective wound healing necessary. Recently, researchers have investigated the design and development of nanoparticles, especially inorganic metal nanoparticles, as promising candidates for addressing various pathological conditions, including wound healing. Several research groups, including ours, have designed numerous metal nanoparticles (including silver, gold, zinc oxide, cerium oxide, terbium hydroxide, silica, titanium oxide, copper) and demonstrated their wound-healing properties using in vitro and in vivo models. The rise of nanotechnology-based platforms in wound healing is evidenced by the tremendous impact and number of publications observed in recent years, which has emphasized the robust potential of inorganic nanomedicine for addressing wounds. Therefore, the importance of these inorganic nanomaterial-based interventions for wound-healing applications needs to be emphasized to inform and encourage scientists and young researchers globally to engage with this expanding area of biology and medicine. In this review article, we mainly focus on highlighting the role of inorganic nanomaterials and nanomaterial-based approaches for wound healing and tissue regeneration, along with their mechanistic properties, clinical status, challenges, and future directions.