Table 3:

Summary of in vitro studies evaluating the biocompatibility and toxicity of cargo-loaded and native VNPs

Plant VNP	Formulation composition	Dose	Cell type	Biocompatibility-/toxicity-related outcomes	IC₅₀	Ref.

Drug delivery studies

CPMV	Native CPMV and CPMV loaded with mitoxantrone (MTO) with and without combination of TNF-related apoptosis inducing ligand (TRAIL)	0.05–5000 nM MTO, with 20–50 MTO molecules/CPMV	U87-MG cells	Up to 10⁷ particles per cell, native CPMV showed no cytotoxicity, while MTO - loaded CPMV (with/out TRAIL) exhibited marked cytotoxicity over 72 hrs	MTO 212.8 nM; Free MTO + TRAIL 65.9 nM; CPMV-MTO 269.0 ± 70.2 nM; CPMV-MTO + TRAIL 153.1 nM	[121]
HCRSV	Doxorubicin (DOX)-loaded HCRSV particles decorated with folic acid (FA)	0.005–30 μg/mL DOX, with 900 DOX molecules/protein cage	ovarian cancer cells OVCAR-3 and normal cells CCL-186	Following 2 hrs of incubation, no cytotoxicity was observed on normal cells, but rather protection against the cytotoxic effects of doxorubicin	DOX 0.48 μg/mL; FA-HCRSV-DOX 0.11 μg/mL vs. OVCAR-3 cells DOX 1.95 μg/mL; HCRSV-DOX 3.4 μg/mL; FA-HCRSV-DOX 3.2 μg/mL vs. CCL-186 cells	[86]
PVX	PEGylated PVX loaded with doxorubicin (DOX)	10–50 μM DOX, with 850–1000 DOX molecules/PVX	A2780. MDA-MB-231 and HeLa cells l	Following 24 hrs of incubation, empty PVX showed no cell toxicity, while DOX-loaded PVX was cytotoxic but to lesser extent than free DOX	DOX 0.13 μM; PEG-PVX-DOX 0.78 μM	[207]
PhMV	PhMV loaded with photosensitizer (Zn-EpPor)	0.19 mg/mL	PC-3 cell line	After 48 hrs of incubation, unloaded and Zn-EpPor-loaded PhMV showed no cytotoxicity in the dark, while the latter was cytotoxic following 30 min illumination at 430 nm	ZnEpPor 0.05 μM; PhMV-ZnEpPor 0.03 μM	[208]
TMV	Phenanthriplatin(Pt)-loaded TMV	0.05–100 μM Pt; with 1,000,000 TMV particles per cell	A2780, A2780/CP70, OV81.2, LNCAP, MCF-7, 8988T and MDA-MB-231 cells	While native TMV showed no cytotoxicity, Pt-loaded TMV was cytotoxic	Similar for both Pt and Pt-TMV: 0.293.59 μM depending on cell lines	[80]
TMV	Native and serum albumin (SA)-coated TMV loaded with doxorubicin (DOX)	3.2 nM–2 μM DOX, with 1476–1664 DOX /TMV	MDA-MB231 and 4T1 cells	Native and SA-coated TMV showed no cytotoxicity, while DOX-loaded native and SA-coated TMVs were cytotoxic against cancer cells over 20 hrs	DOX 0.30 μM; TMV-amide-DOX 0.43 μM; TMV-hydrazone-DOX 0.79 μM; SA-TMV-amide-DOX 33.76 μM; SA-TMV-hydrazone-DOX 36.94 μM	[186]

Imaging studies

PhMV	PhMV loaded with Cy5.5 and Gd³⁺ and decorated with PEG and targeting peptides	0.1–0.4 mg/mL PhMV	PC-3 cell line	The modified PhMV showed no significant cytotoxicity after 12–24 hrs of incubation at the concentrations of 10⁷–2×10⁸ particles/cell	-	[90]
TMV	PEGylated and Peptide (DGEA)-decorated TMV loaded with Dy³⁺ complex and Cy7.5 dye	0.1–0.4 mg/mL	PC-3 cell lines	No significant reduction in cell viability was observed after 12–24 hrs of incubation at the concentrations of 10⁵–4×10⁶ particles/cell	-	[88]
TMV	Polydopamine-decorated TMV loaded with Gd³⁺ complex	0.5 mg/mL	PC-3 and 4T1 cell lines	Without irradiation (with 808 nm laser), TMV particles showed no cytotoxicity after 6 hrs of incubation	-	[94]