Enhanced cytotoxicity of gold porphyrin complexes after inclusion in cyclodextrin scaffolds adsorbed on polyethyleneimine-coated gold nanoparticles

Thiolactone chemistry, a versatile platform for macromolecular engineering

This review covers the extensive use of γ-thiolactone chemistry as a versatile and powerful tool for macromolecular engineering and the preparation of various polymer architectures, such as functional, alternating, or sequence-controlled (co)polymers.

Porphyrin/Chlorin Derivatives as Promising Molecules for Therapy of Colorectal Cancer

Colorectal cancer (CRC) is a leading cause of cancer-related death. The demand for new therapeutic approaches has increased attention paid toward therapies with high targeting efficiency, improved selectivity and few side effects. Porphyrins are powerful molecules with exceptional properties and multifunctional uses, and their special affinity to cancer cells makes them the ligands par excellence for anticancer drugs. Porphyrin derivatives are used as the most important photosensitizers (PSs) for photodynamic therapy (PDT), which is a promising approach for anticancer treatment. Nevertheless, the lack of solubility and selectivity of the large majority of these macrocycles led to the development of different photosensitizer complexes. In addition, targeting agents or nanoparticles were used to increase the efficiency of these macrocycles for PDT applications. On the other hand, gold tetrapyrrolic macrocycles alone showed very interesting chemotherapeutic activity without PDT. In this review, we discuss the most important porphyrin derivatives, alone or associated with other drugs, which have been found effective against CRC, as we describe their modifications and developments through substitutions and delivery systems.

Cyclodextrins-modified metallic nanoparticles for effective cancer therapy

Cancer, a disease of unknown origin is the second most common reason of death worldwide after heart attacks and therefore is a major threat to human beings. Currently, chemotherapy is the only approach for delivering anti-cancer drugs but shows severe systemic toxicities such as alopecia, loss of appetite, anemia, gastric irritation, neurotoxicity and nephrotoxicity. Additionally, chemotherapeutics fails to achieve the expected therapeutic outcome due to their limited solubility, in-vivo instability and lack of targeting efficiency. Encapsulating drugs in metallic nanoparticles like gold, silver and metal oxides (magnetic) help to overcome limitations of chemotherapy and transports anti-cancer drugs effectively at the targeted site due to the advantages such as optimal size, surface morphology, higher conductivity and in-vivo stability. Moreover, these metals can be triggered externally using NIR radiations or magnetic field thereby improving the drug release kinetics. Some frequently used chemotherapeutic agents such as doxorubicin, paclitaxel, methotrexate, etc. degrade rapidly due to their hydrophobic nature and show in-vivo instability. Cyclodextrin offers structural compatibility for encapsulating such hydrophobic drugs and improves their loading capacity, solubility and stability without showing any systemic toxicities. Therefore, researchers designed cyclodextrin-complexed metallic nanoparticles as a novel platform to overcome pitfalls of conventional chemotherapy like gastric irritation, hair loss, neurotoxicity, etc. This review article provides detail insight of metallic nanocarriers containing cyclodextrin-encapsulated anti-cancer agents for effective cancer therapy. It can be concluded that this novel approach holds a great potential for clinical application in cancer diagnosis, treatment with minimum toxicity and maximum efficacy.

A New Approach for β-Cyclodextrin Conjugated Drug Delivery System in Cancer Therapy

Natural cyclodextrins (CDs) are macrocyclic starch molecules discovered a decade ago, in which α-, β-, and γ-CD were commonly used. They originally acted as pharmaceutical excipients to enhance the aqueous solubility and alter the physicochemical properties of drugs that fall under class II and IV categories according to the Biopharmaceutics Classification System (BPS). The industrial significance of CDs became apparent during the 1970s as scientists started to discover more of CD's potential in chemical modifications and the formation of inclusion complexes. CDs can help in masking and prolonging the half-life of drugs used in cancer. Multiple optimization techniques were discovered to prepare the derivatives of CDs and increase their complexation and drug delivery efficiency. In recent years, due to the advancement of nanotechnology in pharmaceutical sectors, there has been growing interest in CDs. This review mainly focuses on the formulation of cyclodextrin conjugated nanocarriers using graphenes, carbon nanotubes, nanosponges, hydrogels, dendrimers, and polymers to achieve drug-release characteristics specific to cells. These approaches benefit the discovery of novel anti-cancer treatments, solubilization of new drug compounds, and cell specific drug delivery properties. Due to these unique properties of CDs, they are essential in achieving and enhancing tumor-specific cancer treatment.

Tailored porphyrin–gold nanoparticles for biomedical applications

In this review we present an updated survey of the main synthesis methods of gold nanoparticles (AuNPs) in order to obtain various tailored nanosystems for biomedical imaging. The synthesis approach significantly impacts on the AuNPs properties such as surface chemistry, biocompatibility and cytotoxicity. In recent years, nanomedicine emphasized the development of functionalized AuNPs for biomedical imaging. AuNPs are a good option for used as delivery photosensitizer agents for PDT of cancer. For example, the complex formed from AuNPs functionalized with PEGylate porphyrins presents several advantages in the medical field such as a better use in photodynamic therapy because of high triplet states and singlet oxygen quantum yield efficiency of porphyrin molecules.

Green synthesis and bactericidal activities of isotropic and anisotropic spherical gold nanoparticles produced using Peganum harmala L leaf and seed extracts

Shape, size, and homogeneity affect the biological activity of gold nanoparticles (AuNPs) in nanomedicine and catalytic applications. Here we biosynthesized monodispersed isotropic and polydispersed anisotropic spherical AuNPs from leaf and seed extract broths of the medicinal plant Peganum harmala L. (Ph. L). Synthesized AuNPs were characterized by ultraviolet-visible spectroscopy, Fourier-transform infrared spectroscopy (FT-IRS), field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM). The antimicrobial activity of AuNPs against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) human pathogens was also assessed. Leaf- and seed-derived AuNPs had characteristic localized surface plasmon resonances of 530 and 578 nm, respectively. TEM, FE-SEM, EDX, and XRD revealed the formation of elemental face-centered cubic spherical monodispersed isotropic AuNPs of average size 43.44 nm and polydispersed anisotropic AuNPs of average size 52.04 nm from leaf and seed extract broths, respectively. FT-IR revealed polyphenols and alcohols as responsible for AuNP capping, reduction, and protection. Anisotropic AuNPs showed no antibacterial activity, whereas isotropic AuNPs showed good inhibition of both E. coli and S. aureus. This represents a simple and ecofriendly protocol for the green synthesis of monodispersed isotropic spherical AuNPs, which may have value in a variety of applications.