The synthesis of semiconducting polymer nanospheres (SPNs) by miniemulsion methods has been reported previously, 1,2 however the resulting materials have typically been significantly larger than quantum dots, the nanomaterial of choice for cell imaging. In the current work, we aimed to obtain quantum-dot-sized poly(ethylene-glycol) (PEG) functionalised SPNs by optimising the miniemulsion method reported previously. 1,3 We report that PEG functionalised SPNs with a narrow distribution of quantum dot sizes were successfully synthesised, with mean diameters ranging between 2 and 5 nm. PEG-dithiol was also used in one variant of the syntheses, allowing the purified sample to be examined by mass spectrometry (using sulfur as a reporter), confirming the inclusion of a significant number of PEG molecules in the nanoparticles. Also, the presence of PEG was found to significantly affect the yield of the reaction, suggesting it played a role in nanoparticle formation. The nanoparticles were characterized by TEM, absorption and emission spectroscopy, and were found to be stable in solution for months.

Aqueous bifunctional semiconductor polymer nanoparticles (SPNs), approximately 30 nm in diameter (as measured from electron microscopy), were synthesised using hydrophobic conjugated polymers, amphiphilic phospholipids and a gadolinium-containing lipid. Their fluorescence quantum yields and extinction coefficients were determined, and their MRI T₁-weighted relaxation times in water were measured. The bimodal nanoparticles were readily taken up by HeLa and murine macrophage-like J774 cells as demonstrated by confocal laser scanning microscopy, and were found to be MRI-active, generating a linear relationship between T₁-weighted relaxation rates and gadolinium concentrations The synthesis is relatively simple, and can easily result in milligrams of materials, although we fully expect scale-up to the gram level to be easily realised.

Photoluminescent conjugated polymeric nanoparticles (CPNs) exhibit favourable properties as fluorescent probes due to their brightness, high photostability, tunable emission spectra and ease of surface modification.

The second harmonic wavelength of a neodymium-doped yttrium-aluminum-garnet (Nd-YAG) laser (λ=532 nm) was used in a pulsed laser ablation technique (PLAL) to synthesize aluminum nanoparticles suspended in white vinegar from an aluminum target. The nanoparticles were characterized by HRTEM and UV-Vis spectrophotometry. They were found to range in size between 2 and 50 nm in diameter, with an average diameter of 12±9 nm. The nanoparticles had a maximum absorption peak at 237 nm and were found to exhibit a core-shell structure with an Al core coated by a thin layer of an amorphous material which could be attributed to amorphous carbon. HRTEM results revealed that the small nanoparticles (<20 nm) had an fcc phase of aluminum crystalline structure, where the larger particles represented alumina (γ-Al2O3) nanoparticles. Such observation suggests that the use of white vinegar as an ablation medium could facilitate the synthesis of aluminum nanoparticles with minimal evidence of the existence of aluminum oxide nanoparticles in the resultant suspension.

Tunable nanoparticle photoluminescence was observed in nanoparticles formed from a polyblend of F8BT, MEH-PPV, and CN-PPV. This phenomena was attributed to direct and indirect inter-chain interactions between the polymers within each nanoparticle.

Gold nanoparticles were synthesised in toluene and stabilised by a fluorescent conjugated polymer (F8BT). The gold/conjugated polymer nanoparticles system was also found to be stable in dichloromethane (DCM), exhibiting both fluorescence (quantum yield = 14%) and a surface plasmon in organic solvents