Poly(lactic-co-glycolic acid) (PLGA) nanoparticles have been extensively studied as carriers of a wide variety of drugs. However, the variability in protocols and reporting in nanoscience represents a barrier to advances in new therapies. Recent literature has highlighted the challenge of reproducibility in biomedical research. In this study involving three researchers performing the experiments we therefore verified the repeatability and replicability of PLGA nanoparticles fabricated by the emulsion solvent evaporation method. Furthermore, we investigated how variables during synthesis, isolation, and characterisation of PLGA particles affect the reported particle size and drug encapsulation. Synthesis parameters including emulsification technique, type of polymer, and type of surfactant were investigated. In the isolation process, we tested the effect of washing and filtration. Dynamic light scattering (DLS) was used to determine the number weighted mean, z-average, and polydispersity index (PDI). Direct visualization of the particles was achieved by scanning and transmission electron microscopies. Changes in the source of energy input to the system using a sonic probe and homogeniser showed the most pronounced effect on particle size and PDI. This work has demonstrated that particle properties are affected by multiple variables involved in the synthesis and isolation processes. We provided advice for PLGA-based nanoparticle fabrication and drug encapsulation quantification as well as the minimum required information to be reported allowing reproducibility.

Alginate (Alg) polymers have received much attention due to the mild conditions required for gel formation and their good bio‐acceptability. However, due to limited interactions with cells, many drugs, and biomolecules, chemically modified alginates are of great interest. Sulfated alginate (S–Alg) is a promising heparin‐mimetic that continues to be investigated both as a drug molecule and as a component of biomaterials. Herein, the S–Alg literature of the past five years (2017–2023) is reviewed. Several methods used to synthesize S–Alg are described, with a focus on new advances in characterization and stereoselectivity. Material fabrication is another focus and spans bulk materials, particles, scaffolds, coatings, and part of multicomponent biomaterials. The new application of S–Alg as an antitumor agent is highlighted together with studies evaluating safety and biodistribution. The high binding affinity of S–Alg for various drugs and heparin‐binding proteins is exploited extensively in biomaterial design to tune the encapsulation and release of these agents and this aspect is covered in detail. Recommondations include publishing key material properties to allow reproducibility, careful selection of appropriate sulfation strategies, the use of cross–linking strategies other than ionic cross–linking for material fabrication, and more detailed toxicity and biodistribution studies to inform future work.

Bone metastasized breast cancer reduces the quality of life and median survival. Targeted delivery of small interfering RNA (siRNA) and chemotherapeutic drugs using nanoparticles (NPs) is a promising strategy to overcome current limitations in treating these metastatic breast cancers. This research develops alendronate conjugated polyethylene glycol functionalized chitosan (ALD‐PEG‐CHI) NP for the delivery of cell death siRNA (CD‐siRNA) and curcumin (CUR) and explores its targeting ability and in vitro cell cytotoxicity. Polyethylene glycol functionalized CHI (mPEG‐CHI) NPs serve as control. The size of CD‐siRNA loaded NPs is below 100 nm while CUR loaded NPs is below 200 nm, with near neutral zeta potential for all NPs. The CUR encapsulation efficiency (EE) is 70% and 88% for targeted and control NPs, respectively, while complete encapsulation of CD‐siRNA is achieved in both NP systems. The bone targeting ability of CY5‐dsDNA loaded ALD‐PEG‐CHI NPs using hydroxyapatite discs is fivefold compared to control indicating ALD presentation at the targeting NP surface. Delivery of CD‐siRNA loaded NPs and CUR loaded NPs show synergistic and additive growth inhibition effects against MCF‐7 cells by mPEG‐CHI and ALD‐PEG‐CHI NPs, respectively. Overall, these in vitro results illustrate the potential of the targeted NPs as an effective therapeutic system toward bone metastasized breast cancer.