Glycol Chitosan-Poly(lactic acid) Conjugate Nanoparticles Encapsulating Ciprofloxacin: A Mucoadhesive, Antiquorum-Sensing, and Biofilm-Disrupting Treatment Modality for Bacterial Keratitis

Bacterial keratitis (BK) causes visual morbidity/blindness if not treated effectively. Here, ciprofloxacin (CIP)-loaded nanoparticles (NPs) using glycol chitosan (GC) and poly(lactic acid) (PLA) conjugate at three different ratios (CIP@GC(PLA) NPs (1:1,5,15)) were fabricated. CIP@GC(PLA) NPs (1:1) were more effective than other tested ratios, indicating the importance of optimal hydrophobic/hydrophilic balance for corneal penetration and preventing bacterial invasion. The CIP@GC(PLA) (NPs) (1:1) realized the highest association with human corneal epithelial cells, which were nonirritant to the hen's egg-chorioallantoic membrane test (HET-CAM test) and demonstrated significant antibacterial response in the in vitro minimum inhibitory, bactericidal, live-dead cells, zone of inhibition, and biofilm inhibition assays against the keratitis-inducing pathogen Pseudomonas aeruginosa. The antiquorum sensing activity of GC has been explored for the first time. The NPs disrupted the bacterial quorum sensing by inhibiting the production of virulence factors, including acyl homoserine lactones, pyocyanin, and motility, and caused significant downregulation of quorum sensing associated genes. In the in vivo studies, CIP@GC(PLA) NPs (1:1) displayed ocular retention in vivo (∼6 h) and decreased the opacity and the bacterial load effectively. Overall, the CIP@GC(PLA) NP (1:1) is a biofilm-disrupting antiquorum sensing treatment regimen with clinical translation potential in BK.

Polymeric graphene oxide nanoparticles loaded with doxorubicin for combined photothermal and chemotherapy in triple negative breast cancer

Combining photothermal and chemotherapy is an emerging strategy for tumor irradiation in a minimally invasive manner, utilizing photothermal transduction agents and anticancer drugs. The present work developed a 2D carbon nanomaterial graphene oxide (GO)-based nanoplatform that converted to 3D colloidal spherical structures upon functionalization with an amphiphilic polymer mPEG-PLA (1, 0.5/1/2) and entrapped doxorubicin (Dox) physically. The Dox@GO(mPP) (1/0.5) NPs displayed the least particle size (161 nm), the highest stability with no aggregation, the highest Dox loading (6.3 %) and encapsulation efficiency (70 %). The therapeutic efficacy was determined in vitro and in vivo using murine (4 T1) and human triple-negative breast cancer cells (MDA-MB-231), and 4 T1-Luc-tumor bearing mouse models. The results demonstrated that the Dox@GO(mPP) (1/0.5) NPs treatment with laser (+L) (808 nm) was highly efficient in inducing apoptosis, cell cycle arrest (G2/M) phase, significant cytotoxicity, mitochondrial membrane depolarization, ROS generation, and photothermal effect leading to a higher proportion of cell death than free Dox, and Dox@GO(mPP) (1/0.5) NPs (-L). The anticancer studies in mice harboring the 4 T1-Luc tumor showed that combination of Dox@GO(mPP) (1/0.5) NPs (+L) effectively reduced tumor development and decreased lung metastasis. The developed nanoplatform could be a promising combination chemo-photothermal treatment option for triple-negative breast cancer.

Hypoxia alleviating platinum(IV)/chlorin e6-based combination chemotherapeutic-photodynamic nanomedicine for oropharyngeal carcinoma

Hypoxia is an important pathological hallmark of the tumor microenvironment, associated with metabolic alterations, cell proliferation, aggressiveness, metastasis, and therapy resistance in cancers. Hypoxia impedes the outcome of photodynamic therapy (PDT), which is largely dependent on molecular oxygen to generate cytotoxic ¹O₂. Here, a near-infrared light activatable, oxygen-generating nanomicellar PDT-chemotherapy system (mPPCPN Ms) constituted of amphiphilic mPEG-PLA, photosensitizer Ce6, and tetravalent platinum prodrug Pt(IV)-diazide was developed for oral squamous cell carcinoma. The polymer conjugate self-assemble to nanosize (115 ± 2.35 nm) micelles, which, upon irradiation (660 nm laser), activated Ce6, and photodecomposed to produce cytotoxic Pt(II), azidyl radical, and molecular oxygen. The strategically fabricated PDT-chemotherapy produced a strong antitumor response in vitro using oral squamous cell carcinoma and in vivo in oral cancer-xenografted mouse models, revealing its significant potential in chemo-photodynamic combination therapy with the benefit of reversing hypoxia.

Nanotherapeutic Intervention in Photodynamic Therapy for Cancer

The clinical need for photodynamic therapy (PDT) has been growing for several decades. Notably, PDT is often used in oncology to treat a variety of tumors since it is a low-risk therapy with excellent selectivity, does not conflict with other therapies, and may be repeated as necessary. The mechanism of action of PDT is the photoactivation of a particular photosensitizer (PS) in a tumor microenvironment in the presence of oxygen. During PDT, cancer cells produce singlet oxygen (¹O₂) and reactive oxygen species (ROS) upon activation of PSs by irradiation, which efficiently kills the tumor. However, PDT's effectiveness in curing a deep-seated malignancy is constrained by three key reasons: a tumor's inadequate PS accumulation in tumor tissues, a hypoxic core with low oxygen content in solid tumors, and limited depth of light penetration. PDTs are therefore restricted to the management of thin and superficial cancers. With the development of nanotechnology, PDT's ability to penetrate deep tumor tissues and exert desired therapeutic effects has become a reality. However, further advancement in this field of research is necessary to address the challenges with PDT and ameliorate the therapeutic outcome. This review presents an overview of PSs, the mechanism of loading of PSs, nanomedicine-based solutions for enhancing PDT, and their biological applications including chemodynamic therapy, chemo-photodynamic therapy, PDT-electroporation, photodynamic-photothermal (PDT-PTT) therapy, and PDT-immunotherapy. Furthermore, the review discusses the mechanism of ROS generation in PDT advantages and challenges of PSs in PDT.

Current trends in the use of human serum albumin for drug delivery in cancer

INTRODUCTION

Human serum albumin is the most abundant transport protein in plasma, which has recently been extensively utilized to form nanoparticles for drug delivery in cancer. The primary reason for selecting albumin protein as drug delivery cargo is its excellent biocompatibility, biodegradability, and non-immunogenicity. Moreover, the albumin structure containing three homologous domains constituted of a single polypeptide (585 amino acid) incorporates various hydrophobic drugs by non-covalent interactions. Albumin shows active tumor targeting via their interaction with gp60 and SPARC proteins abundant in the tumor-associated endothelial cells and the tumor microenvironment.

AREAS COVERED

The review discusses the importance of albumin as a drug-carrier system, general procedures to prepare albumin NPs, and the current trends in using albumin-based nanomedicines to deliver various chemotherapeutic agents. The various applications of albumin in the nanomedicines, such as NPs surface modifier and fabrication of hybrid/active-tumor targeted NPs, are delineated based on current trends.

EXPERT OPINION

Nanomedicines have the potential to revolutionize cancer treatment. However, clinical translation is limited majorly due to the lack of suitable nanomaterials offering systemic stability, optimum drug encapsulation, tumor-targeted delivery, sustained drug release, and biocompatibility. The potential of albumin could be explored in nanomedicines fabrication for superior treatment outcomes in cancer.

Multifunctional graphene oxide nanoparticles for drug delivery in cancer

Recent advancements in nanotechnology have enabled us to develop sophisticated multifunctional nanoparticles or nanosystems for targeted diagnosis and treatment of several illnesses, including cancers. To effectively treat any solid tumor, the therapy should preferably target just the malignant cells/tissue with minor damage to normal cells/tissues. Graphene oxide (GO) nanoparticles have gained considerable interest owing to their two-dimensional planar structure, chemical/mechanical stability, excellent photosensitivity, superb conductivity, high surface area, and good biocompatibility in cancer therapy. Many compounds have been functionalized on the surface of GO to increase their biological applications and minimize cytotoxicity. The review presents an overview of the physicochemical characteristics, strategies for various modifications, toxicity and biocompatibility of graphene and graphene oxide, current trends in developing GO-based nano constructs as a drug delivery cargo and other biological applications, including chemo-photothermal therapy, chemo-photodynamic therapy, bioimaging, and theragnosis in cancer. Further, the review discusses the challenges and opportunities of GO, GO-based nanomaterials for the said applications. Overall, the review focuses on the therapeutic potential of strategically developed GO nanomedicines and comprehensively discusses their opportunities and challenges in cancer therapy.

Oxaliplatin delivery via chitosan/vitamin E conjugate micelles for improved efficacy and MDR-reversal in breast cancer

A bioinspired chitosan/vitamin E conjugate (Ch/VES, 1:4) was synthesized, optimized based on chitosan's molecular weight (15, 300 kDa), and was assembled to entrap oxaliplatin (OXPt). 1H NMR, infrared spectroscopy, chromatography, X-ray photoelectron spectroscopy, X-ray diffraction, drug release, hemolysis, and stability studies were performed to characterize OXPt@Ch/VES micelles. The therapeutic efficacy of the micelles was tested in vitro in ER+/PR+/HER2- and triple-negative sensitive/resistant breast cancer cells, MCF-7 and MDA-MB-231 via cellular uptake, cytotoxicity, nuclear staining, DNA fragmentation, mitochondrial membrane potential, ROS generation, apoptosis, and cell cycle assays and in vivo using 4T1(Luc)-tumor-bearing mice. OXPt@Ch/VES Ms exhibited decreased IC50 towards MCF-7, MDA-MB-231 (sensitive/resistant) than OXPt. OXPt@Ch/VES Ms caused extensive DNA damage, mitochondrial depolarization, apoptosis, and cell-growth arrest (G2/M). OXPt@Ch/VES Ms treatment retarded tumor growth significantly, prolonged survival, and decreased nephrotoxicity than OXPt. The OXPt@Ch/VES Ms could serve as a potential nanomedicine to overcome conventional OXPt-mediated drug resistance/nephrotoxicity in breast cancer.

Exosomes Harnessed as Nanocarriers for Cancer Therapy - Current Status and Potential for Future Clinical Applications

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Exosomes are nano structured (50-90 nm) vesicles that originate from endosomal compartment of eukaryotic cells and are secreted into extracellular matrix. In recent years there has been increased interest in exploring exosomes for diagnostic and therapeutic applications. Like many other diseases e.g. neurodegenerative disorders, autoimmune diseases exosomes have large significance in cancer too. Exosomes are known to prevail in large numbers and carry unique cargos in different types of cancers and thus are proving as versatile entities in understanding their biology of cancers and utilized as efficient diagnostic biomarkers in identification of cancer type. In addition to diagnostic applications there has been an increased interest in recent years to exploit exosomes as carriers for delivery of therapeutic agents to target sites as well. This is indebted to their exceptional non-immunogenic and biomimetic properties that prompted researchers to use exosomes as carriers for delivery of therapeutic agents e.g. drugs, genes and peptides. Exosomes also circumvent many drawbacks associated with other lipid or polymeric nanocarriers e.g. low circulation time, lipid toxicities, long term stability etc. However, in spite of many favorable aspects for exosome based therapy there have been a number of challenges too. This review will focus on the current status of the exosome based drug therapy for cancer, the challenges faced and its potential for future clinical use.