Table 2.
Delivery of chemotherapeutics using silk-based particles.
| Drug | Silk Source | Preparation Method | Particle Size | Characterization | Functionalization/Surface Modification | Target/ In Vitro/ In Vivo Model |
Outcome/Findings | Ref |
|---|---|---|---|---|---|---|---|---|
| Doxorubicin | B. mori silk fibroin | Desolvation with acetone | 100 nm | SEM, DLS, Zeta potential Drug loading/release Cellular uptake (CLSM) Cytotoxicity |
Breast cancer/ MCF-7 MCF-7-ADR/ND |
pH-dependent drug release up to 6 days Enhanced endocytic uptake and lysosomal accumulation |
[174] | |
| Nanoprecipitation with acetone | 106 nm |
Size, Zeta potential SEM Encapsulation efficiency Cytotoxicity |
Breast cancer/ MDA-MB-231/ ND |
Simple, quick and reproducible method of particle preparation High drug encapsulation efficiency Sustained drug release |
[175] | |||
| Electrospraying with PVA blends | 600–1800 nm | DLS, Zeta potential SEM, TEM Drug loading/release Cytotoxicity (MTT) Apoptosis assay In vivo study |
Breast cancer/ MDA-MB-231/ tumor xenograft in mice |
Very good monodispersity High drug encapsulation efficiency Controlled drug release for 72h External ultrasound triggered and accelerated drug release |
[176] | |||
| Silk/PVA phase separation within microfluidics device | 2.8–6.8 µm | SEM Drug loading/release Cytotoxicity (MTT) Macrophage activation Cellular uptake (CLSM) |
Neuroblastoma/ KELLY THP-1/ ND |
High drug loading capacity and efficiency pH-dependent drug release Sustained drug release over 23 days Uptake by THP-1 monocytes Macrophage activation in response to silk particle exposure |
[177] | |||
| Salting-out with potassium phosphate | 530 nm | Size, SEM, Zeta potential, FTIR, BET analysis (porous structure) Cytotoxicity (CCK-8) Cellular binding and internalization (FCM, CLSM) |
FA-conjugated | Cervical cancer/ HeLa/ ND |
FA-targeted and pH-responsive particles Controlled drug release up to 32 h Enhanced internalization in cancer cells overexpressing FA receptor Higher cytotoxicity against HeLa cells than particles without functionalization |
[178] | ||
| Acetone nanoprecipitation | 116 nm | DLS, Zeta potential, SEM, FTIR, Drug loading/release Macrophage activation Cytotoxicity (MTT) Cellular uptake (CLSM) |
PEGylated silk | Breast cancer/ MCF-7/ ND |
Increased particle stability Increased clearance time than non-modified particles High drug entrapment efficiency and release capacity pH-dependent drug release over 14 days |
[179] | ||
| A. pernyi silk fibroin | Ion-induced self- assembly | 100–500 nm | Size, Zeta potential, SEM, FTIR, XRD, Drug release Cytotoxicity (Alamar blue) |
Liver cancer/ HepG-2/ ND |
Self-assembly induced by cations (Na+, Ca2+, and Ce3+) RGD-containing silk fibroin material pH-sensitive and sustained drug release up to 11 days |
[180] | ||
| Self-assembly | 30–1000 nm | SEM, FTIR, XRD Drug loading/release |
ND | pH-sensitive and sustained release for over 23 days | [181] | |||
| A. mylitta silk fibroin | Desolvation with acetone | 150–170 nm | TEM, DLS, Zeta potential Drug loading/release Cellular binding and internalization (FCM, CLSM) Cytotoxicity (MTT) Macrophage activation |
FA-conjugated | Breast cancer/ MDA-MB-231/ ND |
Capable of sustained drug release up to 21 days Selective cancer cells targeting Enhanced cellular binding and uptake via endocytosis than non-functionalized particles |
[182] | |
| B. mori silk sericin-chitosan | Two-step crosslinking with chitosan and EDC | 200–300 nm | Drug loading/release Zeta potential Cytotoxicity (CCK-8) Hemolysis assay Plasma coagulation assay In vivo studies |
Breast cancer/ MCF-7 and Liver cancer/ HepG-2/ tumor xenograft in mice |
Excellent colloidal stability Stable in the absence of cryoprotectants Biocompatible in animal study Low systemic toxicity of the released drug |
[44] | ||
| A. pernyi silk sericin | Silk-templated hydroxyapatite (HAp) mineralization | 1.2 µm | SEM, TEM, DLS, FTIR, XRD Drug loading/release Cryo-SEM Cytotoxicity (Alamar blue) Cellular uptake (CLSM) |
Breast cancer/ Bcap-37 and Cervical cancer/ HeLa/ ND |
Uniform and porous microparticles pH-responsive characteristic due to the presence of pH-responsive HAp Controlled and sustained release of drug |
[46] | ||
| Bioengineered silk (SELP) | Self-assembly with hydrophobic Dox | 50–142 nm | DLS, Drug loading/release Cytotoxicity (MTT) Cellular binding (FCM) and uptake (CLSM) |
Cervical cancer/ HeLa/ ND |
Fabricated and loaded with an aqueous process under mild conditions Simple method to control particle size High uptake of the nanoparticles by the cancer cells Internalization of the nanoparticles through endocytosis |
[37] | ||
| Bioengineered N. clavipes spider silk (MS1) | Salting-out with potassium phosphate | 300–400 nm | Size, Zeta potential, SEM, FTIR, Drug loading/release Cellular binding (FCM) and uptake (CLSM) Cytotoxicity (MTT) |
H2.1 and H2.2 peptides-conjugated (anti-Her2) | Breast cancer/ SKBR-3 and Ovarian cancer/ SKOV-3/ ND |
pH-dependent drug release up to 15 days Enhanced targeted binding to Her2-overexpressing cells Enhanced internalization into targeted cancer cells Higher toxicity towards cancer cells than control cells No cytotoxic |
[88,89] |
|
| In vivo studies (toxicity, biodistribution, efficiency) | H2.1 peptide-conjugated | Breast cancer/ murine D2F2 and D2F2E2/ tumor in mice |
Enhanced tumor-specific targeting in vivo than non-functionalized particles No systemic toxicity as compared to free Dox Suppression of cancer cell growth in vivo |
[90] | ||||
| Bioengineered N. clavipes spider silk (MS1, MS2) | Salting-out with potassium phosphate | <400 nm | Size, SEM, Drug loading/release Cellular binding (FCM) and uptake (CLSM) Cytotoxicity (MTT) |
H2.1 peptide/ DOX binding peptide-conjugated | Breast cancer/ SKBR-3/ ND |
pH-dependent drug release up to 7 days Double functionalization of silk spheres for controlled Dox delivery into Her2-positive cancer cells Enhanced targeted binding and internalization into Her2-overexpressing cells Higher drug-loading capacity, binding per cell and cytotoxic effect compared with control spheres, Higher toxicity towards cancer cells than control cells |
[125] | |
| Paclitaxel | B. mori silk fibroin | Desolvation with ethanol and freezing | 270–520 nm | Size, Zeta potential, FTIR, HRSEM, TEM Drug loading/release |
ND | Easy and mild method of particle preparation Particles with controllable shape and size Drug release for over 9 days |
[183] | |
| Desolvation with ethanol | 158–206 nm | Size, Zeta potential, TEM, FTIR, XRD, Drug loading/release Cellular binding (microscopy) Cytotoxicity (MTT) Apoptosis assay In vivo studies (toxicity, efficiency) |
Gastric cancer/ BGC-823 and SGC-7901/ Tumor xenograft in mice |
Sustained drug release for 100 h Drug-induced cytotoxicity when incorporated into nanoparticles Excellent antitumor efficacy in mice No systemic toxicity |
[184] | |||
| Desolvation with ethanol | 100–600 nm | Size, Zeta potential TEM Drug loading/release Cellular uptake (CLSM) Cytotoxicity |
Cervical cancer/ HeLa and Liver cancer/ HepG-2/ ND |
Dual drug loading (Ptx, Dox) Controlled and sustained drug release for over 7 days High cellular uptake via endocytosis Suppression of cancer cell growth in vitro |
[185] | |||
| Desolvation with acetone | 115 nm | DLS, SEM, FTIR Drug loading (UHPLC-MS/MS) Cytotoxicity (MTT) |
Pancreatic cancer/ CFPAC-1/ ND |
The drug-encapsulation in nanoparticles did not influence its cytotoxicity profile High dose-dependent cytotoxic activity of drug-loaded nanoparticles |
[186] | |||
| Desolvation with ethanol | 186 nm | Size, Zeta potential, FTIR, TEM, Cytotoxicity (MTT) Cellular binding (fluorescence microscopy) In vivo study (biodistribution, efficiency) |
Anti-iRGD-EGFR-conjugated | Cervical cancer/ HeLa/ Tumor xenograft in mice |
High drug content and loading efficiency Enhanced tumor-specific targeting in vitro and in vivo than non-functionalized particles Good antitumor effect |
[187] | ||
| A. mylitta silk sericin | Self-assembly with pluronic surfactants | 100–110 nm | DLS, TEM Fluorescence microscopy Cytotoxicity (MTT) Apoptosis assay (FCM, CLSM, western blot) |
Breast cancer/ MCF-7/ ND |
High loading of hydrophobic drug Stable in aqueous solution High cellular uptake Efficient cytotoxicity towards cancer cells when loaded with drug |
[43] | ||
| Cisplatin | B. mori silk fibroin | Electrospraying | 59 nm | SEM, DLS, FTIR Drug loading/release Cytotoxicity (MTT) Apoptosis assay (FCM) |
Lung cancer/ A-549/ ND |
Drug release for more than 15 days Internalization into cancer cells Sustained and efficient killing of cancer cells Low toxicity in fibroblasts |
[188] | |
| Spray-drying/spray-freeze-drying and crosslinking with genipin |
10.8–22.75 µm | DLS, SEM, AFM, XRD Aerosolization (NGI) Drug release Cytotoxicity (CCK-8, PicoGreen) Cell migration and invasion |
Lung cancer/ A-549/ ND |
Drug loading with or without cross-linking showing different release profiles Drug delivery directly to the lungs via powder inhalers Enhanced cytotoxicity when drug was delivered using the cross-linked particles |
[189] | |||
| Precipitation with ionic liquids and high-power ultrasounds | 173 nm | DLS, TEM, XRD Drug loading/release Cytotoxicity (MTT) Apoptosis assay (flow cytometry) |
Ovarian cancer/ A-780 and A-780-cisR and Breast cancer/ SK-BR-3, MCF-7 and MDA-MB-231/ ND |
Efficient loading with Pt(IV) prodrug PtBz High cellular uptake Overcame drug resistance to cisplatin |
[190] | |||
| 5-Fluorouracil | B. mori silk fibroin | Desolvation with acetone | 278.2–364.9 nm | Drug loading/release Cytotoxicity (CCK-8) Degradation Cellular uptake (CLSM) In vivo studies (toxicity, biodistribution, efficiency) |
cRGDfk and Ce6-conjugated | Gastric cancer/ MGC-803/ tumor xenograft in mice |
Targeted drug delivery and PDT Active tumor targeting Together with laser irradiation, the drug-loaded particles reduced the tumor burden Biocompatibility and safety in vivo |
[127] |
| Desolvation and crosslinking with genipin | 217 nm | TEM, DLS, FTIR Drug loading/release Apoptosis assay (FCM) In vivo studies (toxicity, efficacy) |
Murine breast cancer/ 4T1/ tumor-bearing mice |
Binary drug loading (5-FU and curcumin), High loading efficacy Improvement in the cytotoxic activity and bioavailability compared with free drugs Toxic effect toward cancer cells in vitro and in vivo The anticancer effect observed may be induced by the apoptosis of cells via the generation of cellular ROS |
[191] | |||
| Desolvation with acetone | 220 nm | DLS, Zeta potential, SEM, TEM, FTIR, XRD, Drug loading/release Cytotoxicity (MTT) |
Breast cancer/ MCF-7 Colon cancer/ HT-29 |
High loading efficiency Controlled and sustained drug release Enhanced cytotoxic effect on cancer cells |
[192] | |||
| B. mori pupa protein (Pp) | Desolvation with ethanol | 162 nm | FTIR, Size, Zeta potential Drug loading/release Cytotoxicity (hemolysis assay, MTT) In vivo studies (toxicity, biodistribution, efficacy,) |
Lymphoma/ DAL/ tumor-bearing mice |
Particles that are easy to prepare, modify, with good biocompatibility and bio-adhesivity High entrapment efficiency and capacity Sustained drug release Anticancer efficiency in vivo without causing toxicity in the healthy tissue |
[193] | ||
| FUDR | B. mori silk fibroin | Desolvation with ethanol and freezing | 210–510 nm | Size, Zeta potential, SEM, TEM, Drug loading/release Cytotoxicity (MTT) Cellular uptake (CLSM) |
Cervical cancer/ HeLa/ ND |
Controllable shape and size, without apparent aggregation Drug release time over 2 days Cancer cells growth inhibition Similar curative effect to kill or inhibit Hela cells to the free drug |
[194] | |
| Methotrexate | B. mori silk fibroin | Suspension-enhanced dispersion by supercritical CO2 (SEDS) |
112 nm | FTIR, SEM Drug loading/release Cellular uptake (CLSM) |
Skin from guinea pig | High drug loading efficiency Magnetic nanoparticles for transdermal drug delivery Improved penetration of drugs across the skin |
[195] | |
| B. mori silk fibroin-albumin | Desolvation with acetone and crosslinking with glutaraldehyde | 152–176 nm | TEM, DLS, Zeta potential, FTIR, Drug loading/release Cellular uptake (CLSM) Cytotoxicity (MTT, hemolysis assay) |
Breast cancer/ MDA-MB-231/ ND |
Silk-albumin conjugates High drug loading efficiency Sustained drug release over 12 days |
[109] | ||
| Gemcitabine | B. mori silk fibroin | Desolvation with DMSO | 302 nm | DLS, SEM, Zeta potential Cytotoxicity (MTT) Cellular uptake (CLSM) In vivo studies (biodistribution, toxicity, efficiency) |
SP5-52 peptide-conjugated | Lung cancer/ LL/2/ tumor-bearing mice |
Targeted delivery to lung cancer cells Higher cellular uptake and cytotoxicity in cancer cells in vitro than non-modified particles Increased accumulation in lung tissue than non-modified particles The improved therapeutic outcome in vivo and minimized systemic toxicity than free drug |
[124] |
PVA, poly(vinyl alcohol); DLS, dynamic light scattering; SEM, scanning electron microscopy; TEM, transmission electron microscopy; AFM, atomic force microscopy; FTIR, Fourier-transform infrared spectroscopy; XRD, X-ray diffraction; CLSM, confocal laser scanning microscopy; FCM, flow cytometry; EDC, ethylcarbodiimide; FA, folic acid; PEG, polyethylene glycol; HAp, hydroxyapatite; SELP, silk-elastin-like polymer; Dox, doxorubicin; Ptx, paclitaxel; 5-FU, 5′-fluorouracil; FUDR, floxuridine; Ce6, chlorin e6; PDT, photodynamic therapy; ROS, reactive oxygen species; DMSO, dimethyl sulfoxide.