Soon after they were first described in 1990, aptamers were largely recognized as a new class of biological ligands that can rival antibodies in various analytical, diagnostic, and therapeutic applications. Aptamers are short single-stranded RNA or DNA oligonucleotides capable of folding into complex 3D structures, enabling them to bind to a large variety of targets ranging from small ions to an entire organism. Their high binding specificity and affinity make them comparable to antibodies, but they are superior regarding a longer shelf life, simple production and chemical modification, in addition to low toxicity and immunogenicity. In the past three decades, aptamers have been used in a plethora of therapeutics and drug delivery systems that involve innovative delivery mechanisms and carrying various types of drug cargos. However, the successful translation of aptamer research from bench to bedside has been challenged by several limitations that slow down the realization of promising aptamer applications as therapeutics at the clinical level. The main limitations include the susceptibility to degradation by nucleases, fast renal clearance, low thermal stability, and the limited functional group diversity. The solution to overcome such limitations lies in the chemistry of aptamers. The current review will focus on the recent arts of aptamer chemistry that have been evolved to refine the pharmacological properties of aptamers. Moreover, this review will analyze the advantages and disadvantages of such chemical modifications and how they impact the pharmacological properties of aptamers. Finally, this review will summarize the conjugation strategies of aptamers to nanocarriers for developing targeted drug delivery systems.

Nanomedicine is an emerging field with continuous growth and differentiation. Liposomal formulations are a major platform in nanomedicine, with more than fifteen FDA-approved liposomal products in the market. However, as is the case for other types of nanoparticle-based delivery systems, liposomal formulations and manufacturing is intrinsically complex and associated with a set of dependent and independent variables, rendering experiential optimization a tedious process in general. Quality by design (QbD) is a powerful approach that can be applied in such complex systems to facilitate product development and ensure reproducible manufacturing processes, which are an essential pre-requisite for efficient and safe therapeutics. Input variables (related to materials, processes and experiment design) and the quality attributes for the final liposomal product should follow a systematic and planned experimental design to identify critical variables and optimal formulations/processes, where these elements are subjected to risk assessment. This review discusses the current practices that employ QbD in developing liposomal-based nano-pharmaceuticals.

Aptamers offer a great opportunity to develop innovative drug delivery systems that can deliver cargos specifically into targeted cells. In this study, a chimera consisting of two aptamers was developed to deliver doxorubicin into cancer cells and release the drug in cytoplasm in response to adenosine-5′-triphosphate (ATP) binding. The chimera was composed of the AS1411 anti-nucleolin aptamer for cancer cell targeting and the ATP aptamer for loading and triggering the release of doxorubicin in cells. The chimera was first produced by hybridizing the ATP aptamer with its complementary DNA sequence, which is linked with the AS1411 aptamer via a poly-thymine linker. Doxorubicin was then loaded inside the hybridized DNA region of the chimera. Our results show that the AS1411–ATP aptamer chimera was able to release loaded doxorubicin in cells in response to ATP. In addition, selective uptake of the chimera into cancer cells was demonstrated using flow cytometry. Furthermore, confocal laser scanning microscopy showed the successful delivery of the doxorubicin loaded in chimeras to the nuclei of targeted cells. Moreover, the doxorubicin-loaded chimeras effectively inhibited the growth of cancer cell lines and reduced the cytotoxic effect on the normal cells. Overall, the results of this study show that the AS1411–ATP aptamer chimera could be used as an innovative approach for the selective delivery of doxorubicin to cancer cells, which may improve the therapeutic potency and decrease the off-target cytotoxicity of doxorubicin.

Column chromatography (CC) analysis of methanol and butanol extracts of the aerial parts of Calortopis procera as well as the methanol extract of its latex, led to the isolation of 8 cardenolides, of which the structures were elucidated by NMR and HRESIMS spectroscopy. They also revealed several triterpenes and flavonoid glycoside. Based on the antiproliferative activity reported for cardenolides, the activity of calotropin and calotoxin was tested against two common cancer cell lines, human triple-negative breast cancer cell line (MDA-MB-231) and human lung adenocarcinoma cell line (A549). The high toxicity of the latex also encouraged performing the same test on the same cancer cell lines. The anti-proliferative activity of calotropin and calotoxin was compared to the methanol extract and the wax of the latex. The results showed that calotropin and calotoxin have significant cytotoxicity against MDA-MB-231 and A549 cell lines ranging from 0.046 to 0.072 μM compared to the methanol extract and the wax of its latex ranging from 0.47 to 58.41 μM. Moreover, the results showed lower toxicity of all treatments to the human skin fibroblasts compared to the toxicity to both MDA-MB-231 and A549 cancer cells lines except the higher toxicity of Methanolic extracts of C. procera latex to the MDA-MB-231 cells. In conclusion, C. procera is a medicinal plant with a wide spectrum of cardinolides including calotropin and calotoxin, which are promising agents for targeted cancer phytotherapy.

Diabetes is a major risk factor for osteoporosis, which negatively impacts bone health, but the mechanisms underlying the effects of hyperglycemia on bone marrow mesenchymal/stromal cells (BMSC) are not fully understood. This study investigated how high glucose levels influence BMSC differentiation, proliferation, viability, and metabolism. The results demonstrated that high glucose inhibits osteogenesis in human BMSC, as evidenced by reduced alkaline phosphatase activity, impaired calcium deposition, and downregulation of key osteogenic genes (RUNX2, ALP). Conversely, high glucose conditions promoted adipogenesis, characterized by increased percentage of cells with lipid droplets, and upregulation of adipogenic genes (PPARγ2, CEBPα, AdipoQ), suggesting a shift towards fat cell differentiation. Furthermore, BMSC cultured in high glucose showed decreased proliferation, elevated DNA damage, increased oxidative stress, enhanced apoptosis and senescence, particularly in later passages, highlighting the negative impact of hyperglycemia on BMSC viability. Metabolomic profiling of osteogenic and adipogenic differentiation in normal and high glucose conditions revealed key metabolic shifts, with nicotinamide adenine dinucleotide (NAD+) and l ‐glutamate/α‐ketoglutarate (α‐KG) identified as critical metabolites driving these processes. Supplementation with NAD+ and α‐KG in high glucose conditions significantly enhanced ALP activity. These findings suggest that high glucose promotes adipogenesis at the expense of osteogenesis, exacerbating cellular damage and accelerating aging in BMSC. The identification of NAD+ and α‐KG as key regulators in this process provides new insights into the metabolic mechanisms behind impaired bone health in diabetes and highlights potential therapeutic avenues to counteract these detrimental effects to better manage diabetes‐related bone diseases.