Envisaging marine diatom Thalassiosira weissflogii as a "SMART" drug delivery system for insoluble drugs

Biotemplated Diatom Microrobots for Dual-Drug Delivery in Targeted Neuroblastoma Therapy

Neuroblastoma, a highly malignant pediatric tumor, demands innovative targeted drug delivery strategies to overcome the limitations of conventional therapies. In this study, we developed magnetic diatom microrobots (DMs) using diatom frustules as biotemplates, leveraging their natural hierarchical porosity and biocompatibility. Functionalized with amino groups and folic acid, these microrobots demonstrated enhanced drug conjugation and tumor-targeting capabilities. Designed to carry either cisplatin (CDDP) or paclitaxel (PTX), the DMs facilitated complementary therapeutic effects through pH-responsive release, enabling synergistic neuroblastoma therapy. Magnetic actuation tests confirmed multimodal propulsion and precise motion control. In vitro experiments demonstrated enhanced therapeutic efficacy and reduced off-target effects compared to those of conventional approaches. These diatom-templated magnetic microrobots, with their facile fabrication and superior performance, represent a promising platform for targeted drug delivery and advanced cancer therapy.

A Descriptive Review on the Potential Use of Diatom Biosilica as a Powerful Functional Biomaterial: A Natural Drug Delivery System

Although various chemically synthesized materials are essential in medicine, food, and agriculture, they can exert unexpected side effects on the environment and human health by releasing certain toxic chemicals. Therefore, eco-friendly and biocompatible biomaterials based on natural resources are being actively explored. Recently, biosilica derived from diatoms has attracted attention in various biomedical fields, including drug delivery systems (DDS), due to its uniform porous nano-pattern, hierarchical structure, and abundant silanol functional groups. Importantly, the structural characteristics of diatom biosilica improve the solubility of poorly soluble substances and enable sustained release of loaded drugs. Additionally, diatom biosilica predominantly comprises SiO2, has high biocompatibility, and can easily hybridize with other DDS platforms, including hydrogels and cationic DDS, owing to its strong negative charge and abundant silanol groups. This review explores the potential applications of various diatom biosilica-based DDS in various biomedical fields, with a particular focus on hybrid DDS utilizing them.

Biomimetic Diatom Biosilica and Its Potential for Biomedical Applications and Prospects: A Review

Diatom biosilica is an important natural source of porous silica, with three-dimensional ordered and nanopatterned structures referred to as frustules. The unique features of diatom frustules, such as their high specific surface area, thermal stability, biocompatibility, and adaptable surface chemistry, render diatoms valuable materials for high value-added applications. These attributes make diatoms an exceptional cost-effective raw material for industrial use. The functionalization of diatom biosilica surface improves its biophysical properties and increases the potential applications. This review focuses on the potential uses of diatom biosilica including traditional approaches and recent progress in biomedical applications. Not only well-studied drug delivery systems but also promising uses on bone regeneration and wound healing are covered. Furthermore, considerable aspects and possible future directions for the use of diatom biosilica materials are proposed to develop biomedical applications and merit further exploration.

Marine polysaccharides, proteins, lipids, and silica for drug delivery systems: A review

Marine environments represent an incredible source of biopolymers with potential biomedical applications. Recently, drug delivery studies have received great attention for the increasing need to improve site specificity, therapeutic value, and bioavailability, reducing off-target effects. Marine polymers, such as alginate, carrageenan, collagen, chitosan, and silica, have reported unique biochemical features, allowing an efficient binding with drugs, and a controlled release to the target tissue, also obtainable through "green processes". In the present review, we i) analysed the last ten years of scientific peer-reviewed literature; ii) divided the articles based on the achieved experimental phases, tagged as chemistry, drug release, and drug delivery, and iii) compared the best performances among marine polymers extracted from micro- and macro-organisms. Many reviews describe drug carriers from marine organisms, focusing on a single biopolymer or a chemical class. Our study is a groundbreaking literature collection, representing the first thorough investigation of all marine biopolymers described. Most articles report experimental results on the chemical characterisation of marine biopolymers and their in vitro behaviour as drug carriers, although development processes and commercial applications are still in the early stages. Hence, the next efforts should be focused on the sustainable production of marine polymers and final product development.

Recent Progress in Diatom Biosilica: A Natural Nanoporous Silica Material as Sustained Release Carrier

A drug delivery system (DDS) is a useful technology that efficiently delivers a target drug to a patient's specific diseased tissue with minimal side effects. DDS is a convergence of several areas of study, comprising pharmacy, medicine, biotechnology, and chemistry fields. In the traditional pharmacological concept, developing drugs for disease treatment has been the primary research field of pharmacology. The significance of DDS in delivering drugs with optimal formulation to target areas to increase bioavailability and minimize side effects has been recently highlighted. In addition, since the burst release found in various DDS platforms can reduce drug delivery efficiency due to unpredictable drug loss, many recent DDS studies have focused on developing carriers with a sustained release. Among various drug carriers, mesoporous silica DDS (MS-DDS) is applied to various drug administration routes, based on its sustained releases, nanosized porous structures, and excellent solubility for poorly soluble drugs. However, the synthesized MS-DDS has caused complications such as toxicity in the body, long-term accumulation, and poor excretion ability owing to acid treatment-centered manufacturing methods. Therefore, biosilica obtained from diatoms, as a natural MS-DDS, has recently emerged as an alternative to synthesized MS-DDS. This natural silica carrier is an optimal DDS platform because culturing diatoms is easy, and the silica can be separated from diatoms using a simple treatment. In this review, we discuss the manufacturing methods and applications to various disease models based on the advantages of biosilica.

Nanoparticles from Microalgae and Their Biomedical Applications

Over the years, microalgae have been a source of useful compounds mainly used as food and dietary supplements. Recently, microalgae have been used as a source of metabolites that can participate in the synthesis of several nanoparticles through inexpensive and environmentally friendly routes alternative to chemical synthesis. Notably, the occurrence of global health threats focused attention on the microalgae application in the medicinal field. In this review, we report the influence of secondary metabolites from marine and freshwater microalgae and cyanobacteria on the synthesis of nanoparticles that were applied as therapeutics. In addition, the use of isolated compounds on the surface of nanoparticles to combat diseases has also been addressed. Although studies have proven the beneficial effect of high-value bioproducts on microalgae and their potential in medicine, there is still room for understanding their exact role in the human body and translating lab-based research into clinical trials.

Novel Drug and Gene Delivery System and Imaging Agent Based on Marine Diatom Biosilica Nanoparticles

Mesoporous silica nanoparticles (MSNs) have great potential for applications as a drug delivery system (DDS) due to their unique properties such as large pore size, high surface area, biocompatibility, biodegradability, and stable aqueous dispersion. The MSN-mediated DDS can carry chemotherapeutic agents, optical sensors, photothermal agents, short interfering RNA (siRNA), and gene therapeutic agents. The MSN-assisted imaging techniques are applicable in cancer diagnosis. However, their synthesis via a chemical route requires toxic chemicals and is challenging, time-consuming, and energy-intensive, making the process expensive and non-viable. Fortunately, nature has provided a viable alternative material in the form of biosilica from marine resources. In this review, the applications of biosilica nanoparticles synthesized from marine diatoms in the field of drug delivery, biosensing, imaging agents, and regenerative medicine, are highlighted. Insights into the use of biosilica in the field of DDSs are elaborated, with a focus on different strategies to improve the physico-chemical properties with regards to drug loading and release efficiency, targeted delivery, and site-specific binding capacity by surface functionalization. The limitations, as well as the future scope to develop them as potential drug delivery vehicles and imaging agents, in the overall therapeutic management, are discussed.