Purpose <p>Due to the efficient bone targeting of mesoporous silica nanoparticles (MSNs) and polyaspartic acid (PASP), ^99mTc- labeled polyaspartic acid coated mesoporous silica nanoparticles (PASP-mSiO₂-DTPA-^99mTc) are proposed as a potential probe for bone imaging.</p> Methods <p>Polyaspartic acid-conjugated silica nanoparticles (PASP-mSiO₂) were synthesized using aqueous carbodiimide chemistry and characterized by ATR-FTR, FE-SEM, EDX, TEM, TGA and XRD. Radiolabeling of the produced nanoassembly with ^99mTc was carried out via a simple DTPA chelation procedure. Aqueous dispersion of the radiolabeled nanoparticles was intravenously injected into normal mice and the bone targeting efficiency was evaluated.</p> Results <p>The PASP-mSiO₂ nanoassembly was efficiently synthesized and radiolabeled with ^99mTc with a high radiochemical yield (92 ± 0.5%) and sufficient in vitro stability in PBS and FBS for up to 24&#xa0;h. In vivo biodistribution studies revealed a significant enhancement of radioactivity bone uptake after intravenous injection of PASP-mSiO₂-DTPA-^99mTc compared to radiolabeled uncoated MSNs (mSiO₂-DTPA-^99mTc), (13 ± 0.6% IA/gram and 5.4 ± 0.4, respectively).</p> Conclusion <p>PASP endowed MSNs with enhanced biocompatibility and highly selective bone targeting. Therefore, the proposed PASP-mSiO₂-DTPA-^99mTc nanoassembly has immense potential in the field of bone- imaging via single photon emitting computed tomography (SPECT).</p> Graphical Abstract <p></p>