t-Boc-N-amido-PEG-OH (tBoc-NH-PEG-OH) is a heterofunctional PEG molecule containing an amino protecting group. One end contains a hydroxyl group and the other end contains a Boc-protected amine. The tert-butoxycarbonyl protecting group (t-boc) can be easily removed under acidic conditions to give the free amine. The hydroxyl group can be further derivatized into other compounds.