Despite the enormous therapeutic potential of siRNA as a treatment strategy, the delivery is still a problem due to unfavorable biodistribution profiles and poor intracellular bioavailability. Calcium phosphate (CaP) co-precipitate has been used for nearly 40 years for in vitro transfection due to its non-toxic nature and simplicity of preparation. The surface charge of CaP will be tuned into positive by surface modification, which is important for siRNA loading and crossing cell membrane without enzymatic degradation. The new siRNA carrier system will also promote the siRNA escape from lysosome to achieve siRNA sustained delivery and high-efficiency silence. In this review, we focus on the current research activity in the development of CaP nanoparticles for siRNA delivery. These nanoparticles are mainly classified into lipid coated, polymer coated and various other types for discussion.

Glioblastoma multiforme (GBM) has several distinctive characteristics linked to a poor early-stage prognosis. The crucial obstacle in the treatment of GBM is the inability of chemo drugs or other anticancer medicines to reach brain tumors due to the blood–brain tumor barrier (BBTB), leading to weak cytotoxic activity and drug resistance. Additionally, there is a limited number of clinically approved anticancer medicines for GBM because of the heterogeneity of this type of tumor. Presently, four FDA-approved drugs are available for the treatment of GBM, i.e., temozolomide, lomustine, carmustine, and bevacizumab. These drugs are primarily used to treat recurrent high-grade gliomas and their symptoms. Unfortunately, despite efforts to treat GBM over the last 60 years, no significant progress has been made in extending the overall survival (OS) of patients with this disease. Therefore, possible treatments and accessible drugs must be modified or advanced medicines developed to treat GBM. Several innovative strategies have been used to overcome these challenges, such as combining traditional therapies with emerging nanoscale-based biomaterials for multifunctional characteristics. These modified nanoscale biomaterials can cross the blood–brain barrier (BBB) and increase chemo-drug sensitivity through improved accumulation and efficiency. Herein, we review the recent developments in organic and inorganic biomaterial-based nanoparticles for GBM drug delivery. Firstly, we present a brief overview of the FDA-approved drugs and some additional chemo drugs for treating GBM, followed by a discussion on the drawbacks of the delivery of these drugs in GBM. Further, the current challenges in the field of GBM drug delivery, significant advancements in biomaterials research to overcome these obstacles, and subsequent considerations and opportunities for the application of biomaterials in the clinical treatment of GBM are highlighted.

Pancreatic carcinoma (PC) is greatly induced by the KRAS gene mutation, but effective targeted delivery for gene therapy has not existed. Small interfering ribonucleic acid (siRNA) serves as an advanced therapeutic modality and holds great promise for cancer treatment. However, the development of a non-toxic and high-efficiency carrier system to accurately deliver siRNA into cells for siRNA-targeted gene silencing is still a prodigious challenge. Herein, polyethylenimine (PEI)-modified hydroxyapatite (HAp) nanoparticles (HAp-PEI) were fabricated. The siRNA of the KRAS gene (siKras) was loaded onto the surface of HAp-PEI via electrostatic interaction between siRNA and PEI to design the functionalized HAp-PEI nanoparticle (HAp-PEI/siKras). The HAp-PEI/siKras was internalized into the human PC cells PANC-1 to achieve the maximum transfection efficiency for active tumor targeting. HAp-PEI/siKras effectively knocked down the expression of the KRAS gene and downregulated the expression of the Kras protein in vitro. Furthermore, the treatment with HAp-PEI/siKras resulted in greater anti-PC cells’ (PANC-1, BXPC-3, and CFPAC-1) efficacy in vitro. Additionally, the HAp-PEI exhibited no obvious in vitro cytotoxicity in normal pancreatic HPDE6-C7 cells. These findings provided a promising alternative for the therapeutic route of siRNA-targeted gene engineering for anti-pancreatic cancer therapy.